A partisan standoff that has left the Federal Election Commission unable to function this election year shows no sign of ending.

Senate Majority Leader Harry Reid, D-Nev., on Tuesday offered the White House what he called a “significant concession” to break the impasse over nominations to the FEC, which currently has only two of its six seats filled. But Republicans said he hadn’t offered a substantial change.

The commission has been unable to act this year for lack of a quorum. One of four pending nominees, Democrat Robert Lenhard, withdrew April 14 after waiting months for a vote, which Reid described as a significant loss.

But Republicans have refused to allow separate votes on him or other pending nominees, insisting that all be considered en bloc.

Reid offered in a Tuesday letter to the White House to fill all six seats anew and restore the commission’s ability to function. His offer was based on Bush’s willingness to drop a nominee — Hans von Spakovsky — Republicans have stood behind so far.

“Ultimately, in practical terms, a four-member commission is likely to be as unable to act as the current two-member body,” Reid said, because four votes are needed to enforce rules and pursue litigation. By law, the six members of the commission are evenly split between Republicans and Democrats.

A spokesman for Minority Leader Mitch McConnell, R-Ky., dismissed Reid’s approach. Don Stewart said the proposal only ensures confirmation of three Democrats and “speedy review” of Republican nominees. “We’ve already seen their definition of ‘speedy review’: It’s what led to the current stalemate,” Stewart said. “It would ensure that all three Democrat FEC selections were confirmed, while only one GOP nominee — of the Democrats’ choosing — would be seated.”

The two sitting commissioners are Democrat Ellen Weintraub and Republican David Mason. Bush renominated Mason, and Reid wants Weintraub in place as a “holdover,” even though her term has expired.

Reid would then submit an unidentified Democratic replacement for Lenhard along with already-nominated Democrat Steven Walther.

Reid said Bush has two unnamed Republican nominees cleared for nomination. He assured Bush that Mason would be reconfirmed and suggested the other two would receive “speedy review.”

But Reid’s approach anticipates that von Spakovsky will be dropped by Bush or put to a vote and rejected by the Senate. Democrats oppose his nomination because of the way he handled voting rights cases when working at the Justice Department.

A spokeswoman, Emily Lawrimore, said the White House is reviewing the letter and would comment soon.

The lack of a working panel has left unresolved questions about public financing for Arizona Republican Sen. John McCain’s presidential campaign, fundraising for New York Democrat Sen. Hillary Rodham Clinton’s presidential campaign and ads in congressional special elections.